U.S. patent number 6,623,495 [Application Number 09/766,150] was granted by the patent office on 2003-09-23 for percutaneous material removal device tip.
This patent grant is currently assigned to Edwards Lifesciences Corporation. Invention is credited to Thomas R. Findlay, III, James R. Madonia.
United States Patent |
6,623,495 |
Findlay, III , et
al. |
September 23, 2003 |
Percutaneous material removal device tip
Abstract
A catheter-based material removal device includes an elongated
tube having a distal material removal tip thereon. The material
removal tip includes a one- or two-piece housing affixed to the
tube, and a rotating member therein. The rotating member includes a
screw thread for coarsely chopping material received within the
housing and an outwardly projecting flange for finely chopping the
material. The housing includes at least one shearing member located
axially adjacent the outwardly projecting flange. The shearing
member has a relatively small circumferential size and a shearing
edge that removes any material buildup on the axially-facing
surface of the flange. Two shearing members may be provided, one
each on both the proximal and distal sides of the flange. There may
be three flanges restrained within a groove formed with the
housing. The shearing members are located adjacent to the groove
and may have the shape of teeth, with arcuate inner faces spanning
an included angle through the center of the housing of about 25
degrees. The shearing member on the housing extends inward from a
lumen wall and the shearing edge thereon has a radially oriented
portion and a curvilinear portion blending into tangency with the
lumen wall. In another embodiment, the rotatable member of the
invention includes grinding means for grinding the material prior
to the contact of the material with the shearing member. An article
of manufacture, comprising packaging material and the device of the
invention contained within the packaging material is also
taught.
Inventors: |
Findlay, III; Thomas R. (Laquna
Niguel, CA), Madonia; James R. (Westminster, CA) |
Assignee: |
Edwards Lifesciences
Corporation (Irvine, CA)
|
Family
ID: |
23170288 |
Appl.
No.: |
09/766,150 |
Filed: |
January 18, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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303038 |
Apr 30, 1999 |
6238405 |
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Current U.S.
Class: |
606/159 |
Current CPC
Class: |
A61B
17/320758 (20130101); A61B 2017/00685 (20130101); A61B
2017/320004 (20130101); A61B 2017/320775 (20130101); A61B
2217/005 (20130101) |
Current International
Class: |
A61B
17/22 (20060101); A61B 17/32 (20060101); A61B
17/00 (20060101); A61M 1/00 (20060101); A61B
017/22 () |
Field of
Search: |
;606/159,167,170,171,172,174,180 ;604/22 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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8900059 |
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May 1989 |
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DE |
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442795 |
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Sep 1974 |
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SU |
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665908 |
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Jun 1979 |
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SU |
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WO 89/06517 |
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Jul 1989 |
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WO |
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WO 95/21576 |
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Aug 1995 |
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WO |
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96/11648 |
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Apr 1996 |
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WO |
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WO 98/24372 |
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Jun 1998 |
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WO |
|
Other References
International Search Report for PCT/US99/26845, filed Nov. 11,
1999..
|
Primary Examiner: Truong; Kevin T.
Attorney, Agent or Firm: Edwards Lifesciences LLC Condino;
Debra D. Yadav; Rajiv
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATIONS
This is a continuation-in-part of application Ser. No. 09/303,038,
filed Apr. 30, 1999, now U.S. Pat. No. 6,238,405 the entire
disclosure of which is hereby expressly incorporated herein by
reference.
Claims
What is claimed is:
1. A material removal tip for a catheter-mounted device,
comprising: a rotatable member having a body and at least one
circumferentially spaced outwardly projecting shearing member
having a shearing edge; and a generally tubular housing sized to
receive said rotatable member, said housing including at least one
stationary shearing member having a shearing edge, the stationary
shearing member located axially adjacent said rotating shearing
member for shearing material received in said housing between said
adjacent rotating and stationary shearing members and reduce the
clogging propensity of said material.
2. The device of claim 1, wherein said stationary shearing member
is located distally with respect to said rotating shearing
member.
3. The device of claim 1, wherein said stationary shearing member
is located proximally with respect to said rotating shearing
member.
4. The device of claim 3, further including a second stationary
shearing member located distally with respect to said rotating
shearing member.
5. The device of claim 1, wherein said housing includes proximal
and distal sections, said distal section defining a first lumen for
closely receiving said rotatable member, said proximal section
defining a second lumen coaxial with said first lumen, and a larger
annular groove formed between said first and second lumens for
receiving said rotatable shearing members and axially restricting
movement of said rotatable member, said stationary shearing member
being located adjacent said groove.
6. The device of claim 5, wherein said stationary shearing member
is located distally with respect to said rotatable shearing members
and projects inwardly from said first lumen.
7. The device of claim 5, wherein said stationary shearing member
is located proximally with respect to said rotatable shearing
members and projects inwardly from said second lumen.
8. The device of claim 5, further including a second shearing
member located distally with respect to said rotatable shearing
members and projecting inwardly from said first lumen.
9. The device of claim 5, wherein said housing is formed in one
piece, and said rotatable shearing members are cantilevered with
respect to said body of said rotatable member to enable said
rotatable shearing members to be snap-fit into said groove.
10. The device of claim 5, wherein said proximal and distal
sections of said housing are separate pieces with said groove
defined therebetween.
11. The device of claim 10, wherein said stationary shearing member
is formed on said distal section of said housing.
12. The device of claim 10, wherein said stationary shearing member
is formed on said proximal section of said housing.
13. The device of claim 12, further including a second stationary
shearing member, wherein a first said stationary shearing member is
formed on said proximal section and said second stationary shearing
member is formed on said distal section of said housing.
14. The device of claim 1, wherein said stationary shearing member
has a shearing edge defined by a perpendicular corner on said
shearing member.
15. The device of claim 14, wherein said stationary shearing member
extends radially from a lumenal wall of said housing, and said
shearing edge has a radially oriented portion and a curvilinear
portion transitioning into tangency with said lumenal wall.
16. The device of claim 1, wherein said stationary shearing member
extends radially inward into close proximity with said body of said
rotatable member to define a gap, wherein said gap is more than
zero and less than about 0.254 mm (0.01 inches).
17. The device of claim 1, wherein said stationary shearing member
extends radially inward into close proximity with said body of said
rotatable member to define a gap, wherein said gap is more than
zero and less than about 0.0254 mm (0.001 inches).
18. The device of claim 1, wherein said stationary shearing member
extends radially inward into close proximity with said body of said
rotatable member to define a gap, wherein said gap is more than
zero and less than about 0.0127 mm (0.0005 inches).
19. The device of claim 1 having at least about a plurality of said
stationary and said rotatable shearing members, wherein said
stationary shearing members extend radially inward into close
proximity with said bodies of said rotatable members to define
shearing planes for simultaneous coarse, medium and fine
cutting.
20. The device of claim 1 having a total preselected diameter
effective for use in a preselected body lumen.
21. The device of claim 20 wherein said preselected body lumen is a
blood vessel.
22. The device of claim 20 wherein said preselected body lumen is a
lumen for the passage of bile.
23. The device of claim 20 wherein said preselected body lumen is a
lumen for the passage of urine.
24. The device of claim 20 wherein said preselected body lumen is a
gastrointestinal lumen.
25. The device of claim 20 wherein said preselected body lumen is a
lymph vessel.
26. The device of claim 1, further comprising a lumen, wherein said
lumen is adapted to transport a medically useful agent for release
at a predetermined time.
27. The device of claim 26, wherein said release is accomplished
using pumping means.
28. The device of claim 27, wherein said pumping means is selected
from the group consisting of gas pressure, mechanical pressure, and
liquid pressure.
29. The device of claim 26, wherein said medically useful agent is
an x-ray contrast agent.
30. The device of claim 26, wherein said medically useful agent is
a thrombolytic agent.
31. The device of claim 26, wherein said medically useful agent is
a viral vector agent.
32. The device of claim 26, wherein said medically useful agent is
an enzyme.
33. The device of claim 1, wherein said rotatable member includes
grinding means for grinding said material prior to said contact of
said material with said shearing member, wherein said grinding
means include at least one abrasive surface fabricated from at
least one abrasive material selected from the group consisting of
ceramics, diamond, quartz, silicon carbide, aluminum oxide, boron
carbide, boron nitride, tungsten carbide, titanium nitride,
titanium surfaces with a file-like surface, and stainless steel
surfaces with a file-like surface.
34. The device of claim 33, wherein said rotatable member includes
a grinder rotor having at least a first said abrasive surface, and
said housing includes at least a second said abrasive surface.
35. The device of claim 33, wherein said at least one abrasive
surface includes at least one cutting flute.
36. The device of claim 1, wherein portions of said outwardly
projecting shearing member and said stationary shearing member are
coated with at least one material selected from the group
consisting of ceramics, diamond, quartz, silicon carbide, aluminum
oxide, boron carbide, boron nitride, tungsten carbide and titanium
nitride.
37. The device of claim 1, wherein said outwardly projecting
shearing member and said stationary shearing member are fabricated
from at least one material selected from the group consisting of
ceramics, diamond, quartz, silicon carbide, aluminum oxide, boron
carbide, boron nitride, tungsten carbide and titanium nitride.
38. The device of claim 1, wherein said rotatable member and said
generally tubular housing are constructed substantially of at least
one material selected from the group consisting of stainless steel,
titanium, and acrylic plastic.
39. The device of claim 1, wherein said generally tubular housing
is a one-piece housing.
40. The device of claim 1, wherein said generally tubular housing
is fabricated from at least two pieces, wherein said pieces are
joined by means for joining.
41. The device of claim 40, wherein said means for joining are
selected from the group consisting of welds, adhesives,
press-fitting and mechanical means for interlocking.
42. An article of manufacture, comprising packaging material and
the device of claim 1 contained within said packaging material,
wherein said device is effective for use in a preselected body
lumen; and said packaging material includes a label that indicates
that said device is effective for use in said preselected body
lumen.
43. The article of manufacture of claim 42, further comprising at
least one item selected from the group consisting of guidewires,
introducers, containers, catheters, angioplasty balloons, stents,
medicinal agents, medical syringes, and instructional material.
44. The article of manufacture of claim 43, wherein said
instructional material is at least one device selected from the
group consisting of printed materials, CD disks, magnetic data
storage disks, and videotapes.
45. A material removal tip for a catheter-mounted device,
comprising: a rotatable member having a body and at least one
circumferentially spaced outwardly projecting shearing member; a
generally tubular housing sized to receive the rotatable member,
said housing including at least one stationary shearing member
located axially adjacent said rotatable shearing member for
shearing material received in said housing between said adjacent
rotating and stationary shearing members and reduce the clogging
propensity of said material; and wherein the rotatable member
further includes grinding means for grinding said material prior to
said contact of said material with said shearing member.
46. A material removal tip for a catheter-mounted device,
comprising: a rotatable member having a body and at least one
circumferentially spaced outwardly projecting shearing member; a
generally tubular housing having an internal lumen defining an
internal abrasive surface, the housing being sized to receive the
rotatable member, said housing including at least one stationary
shearing member located axially adjacent said rotatable shearing
member for shearing material received in said housing between said
adjacent rotating and stationary shearing members and reduce the
clogging propensity of said material; and a grinder rotor having a
second abrasive surface located substantially within the tubular
housing lumen.
Description
BACKGROUND OF THE INVENTION
The present invention is related to methods and apparatus for
clearing blocked natural and synthetic vessels, and more
specifically, to methods and apparatus for percutaneously clearing
material from vessels with a rotating device and suction.
A variety of techniques and instruments have been developed for use
in the removal or repair of obstructive material in vessels and
other body passageways. Such material may include atheromas,
thrombi, or emboli. An atheroma is a mass of plaque of degenerated,
thickened arterial intima occurring in atherosclerosis. A thrombus
is an aggregation of blood factors, primarily platelets and fibrin
with entrapment of cellular elements, frequently causing vascular
obstruction at the point of its formation. An embolus is a clot or
other plug brought by the blood from another vessel and forced into
a smaller one, thus obstructing the circulation.
Many catheter-mounted devices are presently available for removing
material from vessels. Some of these devices include rotatable
abrasive members on the distal tip of a flexible catheter, which
tend to remove hardened atherosclerotic materials without damaging
the normal elastic soft tissue of the vessel wall.
Another material removal device is seen in the U.S. Pat. No.
5,423,799 to Shiu, and includes a tubular housing mounted on the
distal end of a catheter within which a helical screw member
rotates. The screw includes a sharp edge which, in cooperation with
housing, cuts the tissue and draws it into the housing for later
removal.
Despite advances made in catheter-mounted material removal devices,
many of them remain limited in their operational capacity, and tend
to clog up fairly quickly. This necessitates the surgeon advancing
very slowly through the material blockage, and greatly increases
the length of surgery. In the worst-case, the device becomes
irreversibly clogged, and must be removed and another device
procured and substituted. Therefore, there remains a need for a
more efficient catheter-mounted material removal device that can
rapidly cut through a mass of blocking material without
clogging.
BRIEF SUMMARY OF THE INVENTION
In one embodiment, the present invention provides a device for
removing material from a body lumen including an elongate, flexible
tube having distal and proximal ends and a passageway therethrough.
The device has a material removal tip on the distal end including
an outer housing rotationally fixed with respect to the tube and a
rotating member within the housing. The housing includes a lumen
extending from a distal open mouth to the tube passageway. The
rotating member includes distal and proximal ends, a central body,
and a plurality of circumferentially spaced flanges extending
radially outward from the body. At least one shearing member is
formed within the lumen of the housing and axially adjacent to the
flange to cooperate with the flange and shear material received in
the housing mouth. The shearing member may be located distally or
proximal with respect to the flanges, or shearing members on both
sides of the flanges may be provided. The housing desirably
includes proximal and distal sections, each including lumens, and
an annular groove larger than either the distal or proximal
sections and formed therebetween for axially restraining the
flanges on the rotating member. The shearing member is preferably
located adjacent to the groove. The housing may be formed in one
piece or two separate pieces.
In a preferred embodiment, the rotating member has a central body
and a helical screw thread thereon and is driven by a drive shaft
that extends through a catheter attached to the housing. The
shearing member has a radial dimension that brings it into close
proximity with an associated rotating member. That is, a distal
shearing member is sized to come into close proximity with the
central body of the rotating member, while a proximal shearing
member is sized to come into close proximity with a drive
shaft.
In another aspect, the present invention provides a material
removal tip for use in a catheter-mounted material removal device,
comprising a rotatable member having an outwardly projecting
shearing member, and a generally tubular housing sized to receive
the rotatable member. The housing includes a stationary shearing
member located axially adjacent to the rotating shearing member.
The stationary and rotating shearing members cooperate to chop
material received within the housing, reducing the clogging
propensity of the material. There is preferably a plurality of
rotating shearing members axially restrained within a groove formed
on the inner surface of the housing. The stationary shearing member
is desirably located adjacent to groove, either proximally,
distally, or both in the case of two stationary shearing
members.
The present invention further provides a method of material
removal, including advancing through a body lumen a
catheter-mounted material removal device having distal material
removal tip including a hollow housing and a rotatable member
therewithin. The rotatable member is rotated to engage the
material, which is then sheared in the housing between relatively
rotating shearing members to reduce the clogging propensity of
material. Subsequently, the sheared material is removed from within
the housing as the device is further advanced through the body
lumen.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view of a hand-held material removal system
within which the material removal device of the present invention
is incorporated;
FIG. 2a is a longitudinal sectional view through one embodiment of
a material removal tip of the present invention having a two-piece
housing;
FIG. 2b is an end elevational view of the material removal tip
having a two-piece housing, taken along line 2b--2b of FIG. 2a;
FIG. 2c is a sectional view of a stationary shearing member of the
proximal housing section in operation, taken along line 2c--2c of
FIG. 2b;
FIG. 2d is a sectional view of a stationary shearing member of the
distal housing section in operation, taken along line 2d--2d of
FIG. 2b;
FIG. 3a is a longitudinal sectional view through a proximal housing
section of the material removal tip of FIG. 2a;
FIG. 3b is an end elevational view of the proximal housing section,
taken along line 3b--3b of FIG. 3a;
FIG. 4a is a longitudinal sectional view through a distal housing
section of the material removal tip of FIG. 2a;
FIG. 4b is an end elevational view of the distal housing section,
taken along line 4b--4b of FIG. 4a;
FIG. 5a is a longitudinal sectional view through a second
embodiment of a material removal tip of the present invention
having a one-piece housing;
FIG. 5b is an end elevational view of the material removal tip
having a one-piece housing, taken along line 5b--5b of FIG. 5a;
FIG. 6a is a longitudinal sectional view through the one-piece
housing of the material removal tip of FIG. 5a;
FIG. 6b is an end elevational view of the one-piece housing, taken
along line 6b--6b of FIG. 6a;
FIG. 7a is a longitudinal sectional view through an alternative
one-piece housing in accordance with the present invention;
FIG. 7b is an end elevational view of the alternative one-piece
housing, taken along line 7b--7b of FIG. 7a.
FIG. 8a is a longitudinal sectional view through a further
embodiment of a material removal tip of the present invention
wherein the rotatable member includes grinding means.
FIG. 8b is an end elevational view of another grinding means of the
invention.
DETAILED DESCRIPTION
With reference to FIG. 1, a material removal system 10 suitable for
use with the present invention comprises an elongate flexible tube
12 having a proximal end 14 and a distal end 16. A hand-held
control 18 attached to the proximal end 14 of the tube 12 permits
manipulation of the system. The control 18 carries electronic
circuitry, controls, and indicators. A source of vacuum 20
communicates with the hand-held control 18 which in turn includes
passages for creating a negative pressure in the interior of the
tube 12. In addition, a drive motor (not shown) is mounted within
the hand-held control 18 for supplying rotational motion to a
flexible drive shaft 22 (FIG. 2a) extending through the elongated
tube 12. A tubular removal passageway 24 is thus defined in the
space outside of the drive shaft 22 and within the flexible tube
12. The drive shaft 22 is preferably hollow to permit passage
therethrough of a guidewire 28.
The present invention provides an improved distal material removal
tip 30, which is shown in detail in FIGS. 2, 3 and 4. The removal
tip 30 comprises an outer housing 32 and a member 34 received
therewithin for rotation about an axis 37. The outer housing 32 has
a substantially hollow tubular shape and comprises a distal section
36 and a proximal section 38, through which a continuous lumen 40
extends. The lumen 40 is defined by a distal lumen 42 within the
distal section 36, a proximal lumen 44 within the proximal section
38, and an annular groove 46 located intermediate the distal and
proximal sections, all being axially aligned. In the illustrated
embodiment, the groove 46 has a larger diameter than the distal
lumen 42, which in turn has a larger diameter than the proximal
lumen 44. The rotatable member 34 is received within the distal
housing section 36, with a portion within the groove 46, as will be
described below.
The aforementioned flexible tube 12 is seen in phantom coaxially
received over a tubular body 50 on the proximal housing section 38.
Likewise, the drive shaft 22 is seen in phantom extending through
the flexible tube 12 and through the proximal lumen 44 into
engagement with the rotatable member 34. In this manner, the drive
shaft 22 and member 34 rotate together within the housing 32. A
number of different drive shaft configurations may be utilized with
the present invention, none of which should be construed as
limiting. Both the elongated tube 12 and drive shaft 22 are seen in
phantom in FIG. 2a, and thus are not seen in the end view of FIG.
2b.
As mentioned, the rotatable member 34 is partly received within the
groove 46. More particular, the rotatable member 34 comprises a
generally cylindrical or tubular body 56 from which a continuous
helical screw thread 58 radially outwardly extends. The screw
thread 58 begins at a distal face 60 of the member 34 and continues
around the body 56 for approximately two-thirds of its length. A
plurality of cantilevered fingers 62 defined by longitudinal slots
64 are provided on the proximal end of the member 34. Each of the
fingers 62 carries an outwardly extending cutter or flange 66, each
of which in axial projection has a generally truncated triangular
shape as seen in FIG. 2b. There are preferably three such flanges
66 evenly circumferentially spaced and forming somewhat of a
propeller configuration about the rotatable member 34. The flanges
66 terminate in outer tips that together define a circle having a
diameter greater than the diameter of the distal lumen 42, but less
than the diameter of the groove 46.
With reference to FIGS. 3a and 3b, the proximal housing section 38
includes the tubular body 50 terminating on its distal end in a
radially outwardly extending annular shoulder 70 having a diameter
that is reduced at a step 72 to a cylindrical land 74 ending at a
distal face 76.
And seen in FIGS. 4a and 4b, the distal housing section 36 also
includes a tubular body 80 extending from a distal mouth 82 to a
proximal end 84. The lumen 42 extends proximally from the mouth 82
until a step 86 increases the diameter to that of a stepped bore
88.
The land 74 of the proximal housing section 38 has a diameter that
is approximately equal to the diameter of the bore 88.
Consequently, the distal end of the proximal housing section 38 is
closely received within the bore 88 until the proximal end 84
contacts the step 72. By cooperation between the distal and
proximal sections 36, 38, the groove 46 is defined on its outer
side by the bore 88, and on respective axial sides by the distal
face 76 of the proximal housing section 38 and the step 86 of the
distal housing section 36. The rotatable member 34 is captured in
the location of FIG. 2a by cooperation between the outwardly
projecting flanges 66 and the groove 46. The cantilevered fingers
62 enable inward deflection of the flanges 66 so that they can pass
through the distal lumen 42 of the housing 32 and snap outward into
the groove 46. The spacing between the flanges 66 and the groove 46
are slightly exaggerated in the drawings, and in a working model of
the device the axial dimension of the flanges 66 will be slightly
smaller than the spacing between the step 86 and the distal face
76. In this manner, the flanges 66 are constrained in the groove 46
from even slight axial movement.
The present invention provides at least one shearing member that is
axially adjacent the flanges 66. In the embodiment of FIGS. 2-4,
there are two such shearing members, a distal member 100 and a
proximal member 102. The distal shearing member 100 projects
radially inwardly with respect to the distal lumen 42 of the distal
housing section 36. Likewise, proximal shearing member 102 projects
radially inwardly with respect to the proximal lumen 44 of the
proximal housing section 38. As seen best in FIG. 4a, the distal
shearing member 100 has a proximal face 104 which is co-extensive
with the step 86. The proximal face 104 is thus positioned on the
edge of the groove 46 closely adjacent to the rotating flanges 66.
In like manner, as seen in FIG. 3a, the proximal shearing member
102 has a distal face 106 which is co-extensive with the distal
face 76 of the proximal housing section 38. The distal face 106 is
thus positioned on the edge of the groove 46 closely adjacent to
the rotating flanges 66.
With reference to the detailed views of FIGS. 3-4, the shearing
members 100, 102 in a preferred embodiment resemble teeth. More
specifically, the distal shearing member 100 includes an arcuate
inner face 110 having a relatively small included angle 112 and
transition surfaces 114 on either side joining the inner face to
the distal lumen 42. The proximal shearing member 102 includes an
arcuate inner face 120 having an included angle 122 and transition
surfaces 124 on either side joining the inner face to the proximal
lumen 44. The small included angles 112, 122 and generally radially
oriented transition surfaces 114, 124 define shearing members 100,
102 of relatively small angular size. The angular size must of
course be sufficient to provide shearing strength in operation, as
will be described, but should be kept to a minimum to reduce the
obstruction to flow of material through the housing 32.
As seen in FIG. 2a, each of the shearing members 100, 102 has a
radial dimension sufficient to bring its respective inner face 110,
120 into close proximity with an adjacent rotating element. That
is, the inner face 110 of the distal shearing member 100 is spaced
across a gap 130 from the body 56 of the rotatable member 34.
Similarly, the inner face 120 of the proximal shearing member 102
is spaced across a gap 132 from the drive shaft 22. The gaps 130
and 132 are preferably minimized without risking contact between
the respective rotating element and shearing member. More
specifically, the gaps 130 and 132 are each desirably greater than
zero but less than 0.254 mm (0.01 inches). More preferably, the
gaps 130 and 132 are each less than 0.0254 mm (0.001 inches), and
most preferably the gaps are each less than 0.0127 mm (0.0005
inches).
Each of the inner faces 110, 120 of the shearing members 100, 102
preferably has an arcuate surface concentric with the axis of
rotation of the adjacent rotating element. In addition, the inner
faces 110, 120 preferably have a radius of curvature that
corresponds to the adjacent rotating elements. Namely, the distal
shearing member 100 has an inner face 110 that is the same radius
of curvature as the body 56 of the rotatable member 34, and the
inner face 120 of the proximal shearing member 102 has a curvature
that is the same as the external diameter of the drive shaft 22. In
one embodiment, the radius of curvature of the inner face 110 is
about 1.194 mm (0.047 inches), and the radius of curvature of the
inner face 120 is about 0.991 mm (0.039 inches).
As illustrated in FIG. 2b, the distal shearing member 100 is
oriented 180 degrees about the housing 32 with respect to the
proximal shearing member 102. In practice, the relative orientation
of the shearing members 100, 102 about the housing 32 is not
considered especially significant. Therefore, the shearing members
100, 102 may be axially aligned, or offset with respect to one
another around the circumference of the housing 32 at any relative
orientation.
The axial and circumferential dimensions of each of the shearing
members 100, 102 must be sufficient to provide adequate strength
without inordinately blocking the lumen 40 through the housing 32.
In one embodiment, the distal lumen 42 has a diameter of
approximately 1.75 mm (0.069 inches), and the distal shearing
member 100 has an axial dimension of approximately 0.279 mm (0.011
inches) and an included angle of approximately 25 degrees. In the
same embodiment, the proximal lumen 44 has a diameter of
approximately 1.42 mm (0.056 inches), and the proximal shearing
member 102 has an axial dimension of approximately 0.318 mm (0.0125
inches) and an included angle about of 25 degrees.
In use, the material removal tip 30 is inserted into a body vessel
or other cavity using the aforementioned guidewire 28 and
conventional catheter introduction techniques not described further
herein. The distal tip 30 is manipulated into close proximity with
the target blockage or material deposit, the drive shaft 22
rotated, and the vacuum source 20 actuated. As the distal tip 30 is
advanced toward the material to be removed, the suction created at
the mouth 82 tends to pull material into contact with the rotatable
member 34 and screw thread 58. The combination of suction and
"Archimedes Screw" action of the screw thread 58 draws material
into the distal housing section 36, and ultimately into contact
with the rotating flanges 66. As the material is drawn through the
distal housing section 36, the screw thread 58 performs a coarse
chopping, reducing the largest material agglomerations in size.
Subsequently, the rotating flanges 66 more finely chop the material
to reduce clogging of the tubular passageway between the drive
shaft 22 and first the proximal lumen 44 and then the inner surface
of the elongated tube 12.
It has been found that without a shearing member, such as provided
by the distal and proximal members 100, 102, material tends to
build up on the axially-facing surfaces of the flanges 66.
Eventually, buildup of material occludes the circumferential spaces
between the flanges 66, greatly diminishing the capacity of
material removal, and in some instances irreversibly clogging the
device. Consequently, the present invention provides one or more
shearing members to cut or otherwise knock material from the
axially facing surfaces of the rotating flanges 66. Because of the
relative movement between the flanges 66 and shearing members 100,
102, the discontinuous circumferential projection of the shearing
members, and the close axial spacing between these relatively
moving surfaces, material is effectively sheared from the axially
facing surfaces of the flanges 66. Any material sheared from the
flanges 66 is then exhausted in a proximal direction through the
annular passageway 24 within the elongated tube 12. The flanges 66
are thus maintained clear of material, and their corners thus
remain unobstructed and effective in finely chopping the material
that reaches them.
With reference to FIGS. 3 and 4, the proximal face 104 of the
distal shearing member 100 and the distal face 106 of the proximal
shearing member 102 are preferably oriented normal to the axis of
rotation 37 of the member 34. In addition, the transition surfaces
114, 124 are preferably axially oriented. As seen in FIGS. 2c and
2d, therefore, the cross-sections (taken circumferentially) of the
shearing members 100, 102 are rectangular, and shearing edges 116,
126 are defined by perpendicular corners that face the leading
edges of the oncoming flanges 66. The leading edges of each of the
flanges 66 are likewise defined by perpendicular corners 68 so that
the passage of the flanges 66 past the shearing members 100, 102
creates a scissor-like action, serving not only to clear material
from the axial surfaces of the flanges 66 but also to sever fibrous
matter present in any material caught therebetween. Alternatively,
one or both of the cooperating edges on the flanges 66 and shearing
members 100, 102 may be sharpened to knife edges to further
facilitate the severing action, although there may be a limit to
such sharpening dictated by strength considerations. FIG. 2c shows
one flange 66 having material adhered thereto and approaching the
proximal shearing member 102, while FIG. 2d shows another flange 66
having just passed the distal shearing member 100 and been cleared
of material.
To further facilitate the two functions of the shearing members
100, 102 (i.e., clearing material from the axial surfaces of the
flanges 66 and also severing fibrous matter), the transition
surfaces 114, 124 each have a radial portion that gradually
transitions to blend into the base lumen wall, as seen in FIGS. 3b
and 4b. That is, the transition surface 114 gradually curves into
tangency with the wall of the distal lumen 42, and the transition
surface 124 gradually curves into tangency with the wall of the
proximal lumen 44. The curvilinear transition surfaces 114, 124
thus provide a radial shear component between the respective
shearing edges 116, 126 and leading edges 68 of the rotating
flanges 66. It will be clear, therefore, that the shearing action
is scissor-like (as opposed to uni-directional shear) as the
oncoming leading edge 68 of each flange 66 first reaches the
radially outermost portion of each shearing edge 116 or 126, and
then gradually reaches the rest of the shearing edge. This is
preferred over a situation where the flange leading edge 68 reaches
the entire shearing edge at once, which would be the case if the
surfaces 114, 124 were entirely radially disposed. Of course, the
latter arrangement is not precluded while still obtaining most of
the benefits of the present invention.
As mentioned above, various other configurations of the material
removal tip 30 are contemplated. For example, FIGS. 5-6 illustrate
a material removal tip 150 having a one-piece housing 152 and a
single shearing member 154. As before, the housing 152 includes a
distal section 160, a proximal section 162, a distal lumen 164, a
proximal lumen 166, and an intermediate groove 168. Likewise, the
rotating member 170, identical to the member 34 previously
described, includes outwardly projecting flanges 172 that are
axially restrained within the groove 168. The elongated tube and
drive shaft are not shown in FIG. 5a for clarity.
As seen best in FIGS. 6a and 6b, the shearing member 154 is located
just proximal to the groove 168, and thus corresponds to the
proximal shearing member 102 described for the first embodiment.
There is no distal shearing member in this embodiment. It all other
aspects, the shearing member 154 is identical to the proximal
shearing member 102 described above, and includes an arcuate inner
face 174 spanning an included angle 176, transition surfaces 178,
and a distal face 180 coincident with the proximal boundary of the
groove 168. The distal face 180 is thus axially adjacent the
rotating flanges 172 and serves to knock material from the proximal
faces of the flanges.
Although only one shearing member is shown located either distally
or proximally with respect to the groove, those skilled in the art
will recognize that two or more shearing members on either side can
also be provided. It has been found that a single shearing member
is sufficient to knock material from the axially facing surfaces of
the flanges, and is preferred because it minimizes the obstruction
to flow of material from the distal to the proximal sections of the
housing. Likewise, as mentioned above, a shearing member provided
of only one side of the rotating flanges is believed to
significantly improve performance of the device. Thus, as seen in
FIGS. 5-6, a single shearing member 154 is provided proximal to the
rotating flanges 172, and another alternative not illustrated is a
single shearing member located distally with respect to the
flanges.
A still further embodiment of the present invention is seen in
FIGS. 7a and 7b. In these views, an alternative one-piece housing
200 is shown for use with a rotating member, such as the members 34
or 170 described previously. Again, the housing 200 includes a
distal section 202, a proximal section 204, a distal lumen 206, a
proximal lumen 208, and an intermediate groove 210. A distal
shearing member 220 and a proximal shearing member 222 are located
on opposite sides and adjacent to the groove 210. The shearing
members 220 and 222 are aligned circumferentially, as seen in the
end view of FIG. 7b.
The choice of using a one- or two-piece housing depends upon the
manufacturing choices available. A one-piece housing is preferred
if tooling for forming the shearing members 220, 222 on the inner
surface thereof is really available. On the other hand, forming the
inner shearing members on the mating ends of each section of a
two-piece housing is somewhat easier, and the two sections can then
be joined with welds, adhesives, press-fitting, mechanical means
for interlocking, or otherwise fastened together.
A number of different materials are suitable for the material
removal device, including stainless-steel, titanium, acrylic or
other suitable biocompatible and rigid materials. The selection of
material may be dictated by the particular manufacturing process
used. In a preferred embodiment, the material removal device
housing is formed in two sections of stainless-steel and includes a
single shearing member on each side of the rotating flanges. The
two sections are preferably laser welded together.
Another embodiment is shown in FIG. 8A and FIG. 8B, wherein the
rotatable member of the invention includes a grinder rotor 300 for
grinding material between abrasive surface 320 on the grinder rotor
and abrasive surface 310 in the housing of the device. This
embodiment may further include at least one cutting flute 330 to
aid the grinding. In the embodiment shown in FIG. 8A and FIG. 8B,
grinding of the material takes place prior to contact of the
material with the shearing member. Abrasive surfaces 310 and 320
may be fabricated from one or more abrasive materials such as
ceramics, diamond, quartz, silicon carbide, aluminum oxide, boron
carbide, boron nitride, tungsten carbide and titanium nitride.
Alternatively, abrasive surfaces 310 and 320 can be titanium or
stainless steel surfaces with a ridged, file-like surface.
Stated briefly, the various embodiments of the invention include a
material removal tip for a catheter-mounted device, comprising a
rotatable member having a body and at least one circumferentially
spaced outwardly projecting shearing member and a generally tubular
housing sized to receive the rotatable member. The housing includes
at least one stationary shearing member located axially adjacent
the shearing member on the rotatable member for shearing material
received in the housing between the adjacent rotating and
stationary shearing members and reduce the clogging propensity of
the material. The stationary shearing member may be located
distally or proximally with respect to the rotating shearing
member, or the rotating shearing member may have stationary
shearing members located both distally and proximally. The
stationary shearing member may have a shearing edge defined by a
perpendicular corner on the shearing member, wherein the stationary
shearing member extends radially from a lumenal wall of the
housing, and the shearing edge has a radially oriented portion and
a curvilinear portion transitioning into tangency with the lumenal
wall.
The invention may include at least about a plurality of stationary
and rotatable shearing members, wherein the stationary shearing
members extend radially inward into close proximity with the body
of the rotatable member to define shearing planes for simultaneous
coarse, medium and fine cutting.
The device may be constructed to be used in a variety of body
lumens. It is useful not only for cardiovascular applications as
already discussed, but may be constructed for use in lumens that
carry bile, urine, lymph, gastrointestinal contents, and the like.
Thus it is applicable to the treatment of gallstones, kidney
stones, intestinal impaction and the like. For any application, the
device is constructed to have a total preselected diameter
effective for use in a preselected body lumen, which lumen may be a
bile lumen, a urine lumen, a gastrointestinal lumen, a blood
vessel, a lymph vessel or the like.
In another embodiment of the invention the device may incorporate
an inner lumen (not shown) adapted to contain a medically useful
agent for release at a predetermined time. The release may be
accomplished using pumping means including gas pressure, mechanical
pressure, and liquid pressure. The medically useful agent can be an
x-ray contrast agent, a thrombolytic agent, a viral vector agent an
enzyme, a proteolytic enzyme or the like medically useful
agents.
In another embodiment, the rotatable member of the invention
includes grinding means for grinding the material prior to the
contact of the material with the shearing member. The grinding
means may comprise one or more abrasive surfaces fabricated from
one or more abrasive materials such as diamond, quartz, silicon
carbide, aluminum oxide, boron carbide, boron nitride, tungsten
carbide and titanium nitride. Alternatively, the grinding means can
be titanium or stainless steel surfaces with a ridged, file-like
surface.
In still further embodiments, portions of the outwardly projecting
shearing member and the stationary shearing member may be coated
with one or more materials capable of forming a sharp cutting edge
such as ceramics, diamond, quartz, silicon carbide, aluminum oxide,
boron carbide, boron nitride, tungsten carbide, titanium nitride
and the like. Alternatively, the outwardly projecting shearing
member and the stationary shearing member may be fabricated from
one or more materials capable of forming a sharp cutting edge such
as ceramics, diamond, quartz, silicon carbide, aluminum oxide,
boron carbide, boron nitride, tungsten carbide, titanium nitride
and the like.
The rotatable member and the generally tubular housing may be
constructed substantially of stainless steel, titanium, acrylic
plastic. and the like biocompatible materials. The generally
tubular housing may be a one-piece housing, or it may be fabricated
from several pieces, wherein the pieces are joined by means for
joining such as welds, adhesives, mechanical means for interlocking
such as press-fitting, and the like.
In a further embodiment, the housing may include proximal and
distal sections, the distal section defining a first lumen for
closely receiving the rotatable member, the proximal section
defining a second lumen coaxial with the first lumen, and a larger
annular groove formed between the first and second lumens for
receiving the rotatable shearing members and axially restricting
movement of the rotatable member, the stationary shearing member
being located adjacent the groove. Here, the stationary shearing
member may be located distally or proximally with respect to the
rotatable shearing members and projects inwardly from the first
lumen. Further, stationary shearing members may be located both
distally and proximally with respect to the rotatable shearing
members and project inwardly from the second lumen. This embodiment
may have a housing is formed in one piece, and rotatable shearing
members cantilevered with respect to the body of the rotatable
member to enable the rotatable shearing members to be snap-fit into
the groove, or the proximal and distal sections of the housing may
be separate pieces with the groove defined therebetween.
Included in the invention is an article of manufacture, comprising
packaging material and the device of the invention contained within
the packaging material, wherein the device is effective for use in
a preselected body lumen; and the packaging material includes a
label that indicates that the device is effective for use in the
preselected body lumen. The article of manufacture may further
include guidewires, introducers, containers, catheters, angioplasty
balloons, stents, medicinal agents, medical syringes, and
instructional material and the like equipment for the procedures in
which the device will be used. The instructional material may
comprise printed materials, CD disks, magnetic data storage disks,
and videotapes, and the like.
The present invention may be embodied in other specific forms
without departing from its spirit or essential characteristics. The
described embodiments are to be considered in all respects only as
illustrative and not restrictive. The scope of the invention is,
therefore, indicated by the appended claims rather than by the
foregoing description. All changes that come within the meaning and
range of equivalency of the claims are to be embraced within their
scope.
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